Headline: The Paris Agreement turns five: It’s high time we tackle the ocean and climate crises together

The effects of climate change on the ocean cannot be considered in isolation.
The effects of climate change on the ocean cannot be considered in isolation. Photo by Pierre Leverrier on Unsplash

We live on a planet interconnected through complex and constantly changing relationships between the various natural and anthropogenic components of the ‘Earth system’. Of these relationships, one of the most critical for human existence is that between the ocean and climate. The effects of climate change on the ocean cannot be considered in isolation, because ocean processes themselves are part of the climate system and thus also modulate climate change. In other words, the ocean-climate nexus is a two-way street, requiring forward looking and innovative governance approaches.

Climate negotiations and the ocean

Five years have passed since the so-called ‘Paris Agreement’ was concluded at the 21st Conference of the Parties (COP) to the UN Framework Convention on Climate Change (UNFCCC) following years of deliberation between the member States. For the ocean, the Paris Agreement represents a turning point: previously, issues relating to the ocean were side-lined in COP negotiations. At COP21, the negotiations saw an increased interest in the ocean and (crucially) the link between the ocean and climate was formally recognised and explicitly noted in the Preamble to the Agreement. The momentum built through the increased attention of States, NGOs and scientists to the link between the ocean and climate paved the way for the concept of the ‘Blue COP’, as COP25 (2019) became known.

Held in Madrid, Spain, the Blue COP was chaired by Chile and faced high expectations among the ocean community, as demonstrated by the numerous events, policy recommendations, forums, and publications surrounding the conference (e.g. The Because the Ocean Initiative). A key outcome of this COP was the agreement to hold an Ocean and Climate Change Dialogue as part of the UNFCCC Climate Dialogues, which took place online in December 2020. The event highlighted the strong link between the ocean and climate, and the need to continue to identify opportunities to strengthen ocean-climate action within the UNFCCC and across UN agencies as well as in future COPs. In particular, COP26, which has been postponed until November 2021 due to the pandemic, has been declared a continuation of the “Blue COP”, ensuring that the ocean remains high on the climate agenda.

The impacts of climate change on the ocean are immense

Ocean health is in a precarious state – and climate change is a major driver of its decline. The IPCC 2019 Special Report on the Ocean and Cryosphere in a Changing Climate is a call to action to global policy makers and the public to urgently address the devastating effects on the ocean of climate change: sea levels are rising and the waters are warming, acidifying and losing oxygen, resulting in serious impacts on marine ecosystems. What we must understand is that when we harm the ocean, we harm the support system for all life on this planet. The future of important keystone species and ecosystems such as warm-water coral reefs, seagrass meadows, and kelp forests is in question if global warming exceeds 2 °C by the end of this century, with significant impacts already expected if 1.5 °C is exceeded (IPCC, 2019).

The direct impacts from warming and deoxygenation as well as the indirect impacts from changes in primary production will imperil essential ocean services such as the supply of protein through seafood production, carbon sequestration, and the mitigation of climate change. The consequences of these effects and related impacts will be felt far into the future, putting at risk other overarching goals such as the attainment of human well-being while safeguarding the planet as set out under the UN’s 2030 Agenda for Sustainable Development, including the ‘ocean goal”, Sustainable Development Goal 14 (Singh et al. 2019). Action to address the impacts of climate change on the ocean must take on this global challenge, while important regional differences must be considered if governance approaches are to adequately address this enormous challenge.

Not all areas of the ocean are affected equally by climate change

Recent research indicates that more than 50 % of the world's oceans could already be affected by climate change today, with up to 80 % being affected in the coming decades. The researchers also found that the ocean of the Southern Hemisphere is affected more rapidly by climate change than that in the Northern Hemisphere. However, changes to the oceans of the Southern Hemisphere are likely to go undetected longer than those in the Northern Hemisphere, as this area is comparatively less observed and sampled.

Improving ocean sciences through increased observations and greater funding in research will be essential to understanding the impact and more accurately predicting the effects of climate change across regions. The socioeconomic impacts of climate change will also differ across marine regions. Fisheries catches and their composition in many regions are already affected by warming, with impacts on the growth, reproduction, and survival of fish stocks (IPCC, 2019), which are likely to experience a net decrease, due to climate change, though this will not be geographically consistent. Fish stocks have already started to shift towards higher latitudes as the climate warms, leading to changes in metabolism that impact life cycles and rates such as faster growth and lower maximum size.

Despite the immense challenge of climate change, the existing regulatory and institutional framework established to conserve ocean biodiversity and sustainably manage fisheries activities is underachieving. These regional variations in terms of effects and impacts call for the development of innovative management and governance solutions by science, policymakers, civil society and industry as there is no one-size fits-all approach in dealing with climate-change related effects and impacts.

Ocean governance and climate change

There is only one ocean and, while responding to regional specificities and setting up harmonized measures at the scale of ocean regions, it is of uttermost importance that we grasp the transboundary and interdependent nature of the ocean: The ocean is ecologically not only boundless due to its world-spanning system of ocean currents or by migration of species. Fluxes of liquid, gaseous and particulate matters also occur between the ocean, the atmosphere, and the land. This ecological connectivity is essential to healthy marine ecosystems across the globe and to the ocean’s role in regulating climate.

Ecological connectivity means that disturbances to marine biological diversity are not contained; rather, they have effects far beyond the immediate area of impact. For example, regions such as upwelling sites or seamounts have an especially high biological productivity and are important to restock marine resources in other marine areas. The negative impacts from climate change such as habitat degradation will impact fisheries in coastal zones, and vice versa. Ocean conservation and management regimes must understand and consider both climate change effects and ecological connectivity to be effective at conserving marine biological and addressing the impacts to all life on this planet. Ecological connectivity demands transboundary, multi-level and cross-sectoral governance approaches for the conservation and sustainable use of marine biological diversity. So in fact, the ocean needs to be protected and managed as a whole in order to respond to climate change and the cumulative pressures stemming from human activities, both on land and at sea.

The ocean as part of the solution

With this enormous task at hand, some researchers and policymakers are asking whether the ocean could be part of the climate solution. Ocean-based conservation measures for mitigating and adapting to climate change exist, but their contribution could be stepped up. Measures range from employing ecosystems (e.g. mangroves, saltmarshes and seagrasses) to absorb and store CO2, to different management options to reduce greenhouse gas emissions from ocean-based activities (e.g. fisheries and transport) or increasing the contribution of renewable energy production from the ocean. Other options include climate intervention or geoengineering – which has until recently gained limited traction and been considered by many to be too radical.

One approach to ocean-based climate intervention is Carbon Dioxide Removal (CDR) through, for example, ocean alkalinity enhancement, which seeks to extract CO2 from the atmosphere and store it in marine ecosystems. To date, most of the focus has been on land-based technologies that allow for ‘negative emissions’ such as bioenergy technologies with carbon capture and storage (BECCS). Particular attention is now being given to the ocean, as these large open spaces that account for 70% of the Earth’s surface have potentially fewer conflicts of interest compared to on land. But while some argue that new ocean-based net emission technologies (NETs) may be indispensable if the climate targets set under the Paris Agreement are to be met, many worry that climate interventions will lead to further harm to the health of an already deteriorated ocean, as it is not known what the impacts of these emerging technologies will be when implemented at large scales.

While some international regulations around such technologies exist, namely within the scope of the Convention on Biological Diversity (CBD) and the International Maritime Organisation (IMO), these remain limited in coverage and scope. With numerous experiments planned, the next question is: What should responsible governance for research, and eventually deployment, look like? Along these lines, the IASS is participating in the EU-funded research project “Ocean-based Negative Emission Technologies - Analyzing the feasibility, risks, and co-benefits of ocean-based negative emission technologies for stabilizing the climate" (OceanNETs). The project will investigate whether ocean-based climate interventions can play a substantial and sustainable role in limiting global warming and will weigh technical, environmental, economic, and social considerations to derive recommendations for policymakers. Within the interdisciplinary consortium, the IASS and its partners from the University of Hamburg aim to analyse the governance, policy, and legal dimensions of ocean-based NETs. More broadly, this research will offer insights on how these emerging technologies fit with the current legal and institutional ocean governance framework, including the goals set under these, and identify and prioritize key policy constraints and possible trade-offs and synergies between current and potential future management regimes.



Edith Green am 18.10.2021 - 12:16

Right now I am very happy about the EU taking the step to ban single-use plastic! We are on the right track I'd say. I also recently discovered the "German Packaging Act", probably most of you have heard of it already. But there is one interesting fact: it applies also to other countries such as the UK now (see here: https://www.lizenzero.de/en/blog/german-packaging-act-in-the-uk-obligations-when-shipping-to-germany/) Let's stop climate change all together.


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